Johnson, 25, had amassed a personal arsenal at his home in the suburb of Mesquite, including bomb-making materials, bulletproof vests, rifles, ammunition and a journal of combat tactics, authorities said on Friday.

Dallas police chief says shooter 'wanted to kill white people'

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Johnson was a private first class with a specialty in carpentry and masonry. He served in the Army Reserve for six years from 2009 and did one tour in Afghanistan from November 2013 to July 2014, the military said.

How the Dallas police shootings unfolded

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Johnson, who donned a protective vest and used a military-style semi-automatic rifle, was killed by a robot-delivered bomb after the shootings on Thursday night, authorities said. It marked the deadliest day for US law enforcement since the September 11, 2001 terrorist attacks.